Recently, terrestrial digital broadcasting has been started in Ultra High Frequency (UHF) band. Each physical channel of a terrestrial digital broadcasting is divided into 13 segments, one segment of which is used for broadcasting for mobile terminals. Then, the remaining 12 segments are used together for broadcasting for fixed terminals, such as television receivers (for example, see Patent Document 1).
Currently, in broadcasting for mobile terminals, the same content as that of broadcasting for fixed terminals is broadcast. Mobile terminals, mainly mobile phones, capable of receiving a broadcasting for mobile terminals have already been widely spread.
Also, in a terrestrial digital broadcasting wave, channels 13 to 52 of UHF band include many unused channels in addition to channels in which terrestrial digital broadcasting is actually performed in various regions. So, a method for effectively utilizing these unused channels is under consideration.
One possible method for effectively utilizing the unused channels is to perform multi-segment broadcasting in the unused channels. Note that multi-segment broadcasting refers to a plurality of one-segment broadcastings simultaneously transmitted in one physical channel. In other words, multi-segment broadcasting refers to broadcasting in which the frequency band of terrestrial digital broadcasting is divided into a plurality of segments and one or more broadcasting services are performed in one segment.
By the way, a conventional mobile terminal for receiving broadcasting for mobile terminals obtains tuning information that is information on tuning, such as frequency, and creates a table of tuning information (hereinafter referred to as tuning table) as follows:
FIG. 1 is a flowchart of tuning table creation by a conventional mobile terminal.
In step S11, the mobile terminal sets a predetermined physical channel (for example, a physical channel with the lowest frequency) as target physical channel to be processed. In step S12, the mobile terminal tunes to the center segment of the target physical channel. In step S13, the mobile terminal determines whether the Transport Stream (TS) of the center segment of the target physical channel has been received or not. If determined that it has been received, the process proceeds to step S14.
In step S14, the mobile terminal obtains, from the received TS, an Network Information Table (NIT) that is information on the network of the segment for the mobile terminal, described as NIT actual, and an Service Description Table (SDT) that is information on the broadcasting service of the network of the segment for the mobile terminal, described as SDT actual. Note that the NIT refers to a table that contains frequency information for each broadcasting service and information on the corresponding broadcasting service for tuning the carrier frequency to a certain broadcasting service. Furthermore, the SDT refers to a table that contains meta-information for each broadcasting service (for example, service name and the like). After the processing in step S14, the process proceeds to step S15.
On the other hand, if determined in step S13 that the TS of the center segment has not been received, the process skips step S14 and proceeds to step S15.
In step S15, the mobile terminal determines whether all of the physical channels have been set as target physical channel or not. If determined in step S15 that not all of the physical channels have been set as target physical channel, in step S16, the mobile terminal sets a next physical channel (for example, a physical channel with the second lowest frequency) as target physical channel, then the process returns to step S12. Then, the mobile terminal repeats the process of steps S12 to S16 until all of the physical channels are set as target physical channel.
On the other hand, if determined in step S15 that all of the physical channels have been set as target physical channel, in step S17, the mobile terminal creates a tuning table based on the NITs and SDTs obtained in step S14.
Specifically, as shown in FIG. 2, the NIT contains a network ID that is an ID unique to a network, a TSID that is an ID unique to a TS, a frequency, a service ID unique to a broadcasting service and the like, corresponding to the segment for the mobile terminal. Furthermore, the SDT contains meta-information on a broadcasting service corresponding to the segment for the mobile terminal, including a TSID, a service ID, a service name and the like, of the broadcasting service.
Thus, as shown in FIG. 2, the mobile terminal obtains the service ID and the frequency as tuning information from the NIT of the center segment of each physical channel, obtains the service name from the SDT corresponding to the NIT, then associates the service name with the frequency to create the tuning table.
Note that, in the example shown in FIG. 2, since two broadcasting services are broadcast in a time-division manner in the center segment of a physical channel 1 (PhCH-1), two service IDs are contained in the NIT of the center segment of the physical channel 1.